>"...but I dont have any clue on how to make it more profitable."

You probably won't fix that in this thread if you don't share the URL or even enough information about your chat site for people to give educated feedback.

What kind of users are they? Do they chat about everything or is there a theme or geographical niche? What kinds of ads are displaying through adsense? How long did it take you to get to 3k users? Do you feel like it will be hard to get more? Why did you throw up adsense at such low traffic?